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    <title>Document</title>
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h1{
    color:red;
}
.h2class{
   color:blue;
}
#h3id{
    color:black;
}

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<title>实验3.1 CSS基础选择器的用法</title>

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<body>

<h1>标签选择器</h1>

<h2 class="h2class">类选择器</h2>

<h3 id="#h3id">ID选择器</h3>

</body>

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